Apparatus for renovating molding sand



March 4, 1941. w. J. BELL APPARATUS FORRENOVATNG MOLDING SAND 2 Sheets-Sheet l Filed 001'.. 26, 1958 ell March 4, 1941. w J, BELL 2,233,728

APPARATUS Foa RENovA'r-ING Momma SAND Filed oct'. ze, 1938 2 sheets-sheet 2 A 35M/mand d. .Beni

21 A uuymwk '2 nomb Patented 'Marr '4, 1941 APPARATUS FOR RENOVATING MOLDING SAND wmara J. Ben. Newaygo, Mich.

Application October 26, 1938, Serial No. 236,980

4 Claims.

This invention relates to an apparatus and a method of renovating molding sand after the same has been used in flasks in casting and from which it isl removed. Such sand coming from 5 the flasks has parts thereof burned, others baked and adhering together. There are pieces of metal and sometimes of wood in the sand and from the burning which has occurred ashes and very fine dust occur, which should be removed. After the sand has been once used in flasks in the operation of molding it is necessary from cost considerations to reuse the sand, with the addition of Water, bonding material and the like, to properly prepare the sand for its subsequent use in molding.

The present invention is concerned with the rst step in the renovation of the used sand and has for its primary object and purpose the breaking up of the chunks and bodies of sand which are packed'or otherwise adhere together, the removal of ashes and dust and the removal of metallicv and wood parts which have come from the'casting, particularly iron fins and the like which are not large enough to be readily removed either manually or in practice-magnetically. i

With my invention the sand -which has been previously used in a casting operation is prepared for mixing with added materials which mustbe supplied before the sand is again in suitable shape for use, and at the same time increase the efficiency of the mixing machine which is thesubject matter of a copending application for patent filed by me on October 26, 1938, and bearing Ser. No. 236,979, and prepare and renovate the sand so that it will mix better, ,freeing the sand of all metallic ilns, pieces of wood and other undesired materials and removingl ashes and dust in a very practical and efcient manner.

An understanding of the invention may be had from the following descriptin,taken in connection with theA accompanying drawings, in which:

Fig. -1 is a vertical section takenv from 'wir` t may be termed the front to the rear of the machine.

Fig. 2 is a vertical section substantially on the plane of line 2-2 of Fig. 1, and

ture relating to the grate or screen bars which are spaced apart and between which the renovated sand is delivered from the machine,

Like reference characters refer to likaffpaxjts in the different figures of the,- drawings.

Fig. 3 is a perspective view of a detail of4 struc- In the construction of the machine a substantially enclosed housing is provided which for purposes of easy assembly is divided horizontally into two parts or sections.- The lower section has spaced apart vertical sides. I between which 5 at their front and rear edges are front and rear vertical end members 2. Angle bars 3 surround this lower portion of the housing at the lower end thereof vand are bolted in place`as shown. The underside of the housing is open, the sand being delivered from the machine at such open under side usually to a conveyor belt which is to carry the renovated sand to the mixing machine for the next step in preparing the sand for mold..

ing use. 15

The upper section of the housing has two spaced apart vertical sides 4 immediately above and in the same plane with the sides I, and `a front 5 immediately above and in the same plane with the front member 2 of the lower part of the 20' housing. The upper and lower sections of the housing are connected together by angle barssuch as indicated at 6 in Fig. 1it being evident that the bolt connections permit a ready assembly of the parts. At the upper side and at the rear part. of the housing is a top 1 .extending over approximately one-half of the upper side of the housing to which a second top or cover -plate 8 is hingedly connected by hinges shown at I0. Angle bars 9 are bolted at the upper ends of the sides for connection of the top member I and the front 5, and the hinged 'cover mem'- -ber 8 may have the bolts which connectit to said angle bars removed, permitting lifting for access to the interior of the machine'when desirable or necessary.

At the inner side of the housing and particularly'at those portions where the sand which is to be operated upon strikes against the housing, it; is lined with wear plates II to Il inclusive. The plates II and I2 are at the inner sides of the sides 4, the wear plates I3 and I4 are of sector-like shape as best shownln Fig. 1 and cover a portion of the lower parts of the side plates 4 and of the upper parts of the side plates yI of the housing. The plate I5 is at the inner side of the vertical front 5 and Vthose at I6 and I1 underneath the cover or top members 1 and 8. Such plates )are bolted in place and can bef readily removed and replaced by'A removing thebolts when after a period of operation of the machine the wearing away ofthe plates has made it advisable that they be; replaced with new ones. -f

Near the lower portion of the housing at each 55 side thereof two spaced apart curved guide bars I8 and are secured at the inner side of each side of the housing. 'Ihe curved edges of the wearing-plates I3 and I4 come against the upper curved edges of the bars I8 (Fig. 1). Between these pairs of spaced apart bars I8 and I9 screen or grate bars 20, preferably of tool steel, are located, extending across from one side to the other of the housing, and having their ends received and guided betWe/e the curved guide bars I8 and I9. Alternate bars 20 -at their ends have wedge blocks 2| secured thereto by a pin 22 (Fig. 3), the wedges serving to space the adjacent;` bars short distances apart and.therebyf.mak ing a. grating or screen for sand `to'pass"through. It is of course to be understood that while, as

' in Fig. 3, alternate bars Acarry both thawedgesi side, thus permiting the bars tobe used twice as long as would bethe case if it was necessary to replace them afterpthe upper edges thereof had become worn.'

The end bars 20 of 'the curved screen or grating come against an angle bar stop 23 "and a' heavy breaker plate 24 whichA hold them against movement or displacement4 The' stop provided 45 to .the top-of the housing. At its .upper .portion by the member 23 is bolted "in 'place at' thej inner side of the front member ofthe housing after end of the entrance chute 28 `and go to the interior of the machine.

A short distance in front of the sand conducting chute 28 is a chimney 29 having a damper 30 therein, the lower end of the chimney communicating with the interior of the machine through openings made in the plates 'I and I6. A fan housing 3| is disposed 4above and connected'to the upper end of the chimney 29 from which anoutlt`32 leads'tdayfdesired' place in the foundry where the machine isl used, the fan acting to draw dust, ashes and other sufciently light materials upwardly and project them out Hthrough thee-outlet at 32, the degree of suction beig 'controlled by the position of the damper 30. Y The hinged cover member 8' has over it a dome shaped-*housing 33, the entire bottom of which id .open at3ato the interior of the machine. A vertical partition 35 extends lengthwise of the .housing 33 and has its upper edge spaced from the top ofjthe, dome. .Forwardly of the partition -.is'locatd algatihgor screen-36 inclined longit'dinallyof' the housing vand having its lower end 'communicating with -a 4disposal pipe 36a. This. dome .and screen .act to eliminate chunks of materialfrom theszandas hereafter explained.

Between their front. and rear edges and at the lower portions thereof the ,sides 4 and the wear plates. at the inner sides thereof are cut away to provide openings3fl; A shaft 38 passes through thev .machine,. at .its-'end portions extending beyond. said openings, and is mounted for rotation in bearings 3.9 carried on horizontal shelves 40 at the .outer 'sides ofthe machine,l and which are supported and reinforcedb'y .braces 4| (Fig. 2). Within the: machine .and bet'weenits sides the '28 which is relatively l thick and heavy'is guided.. by the spaced guides provlded by the angles 25. disks a short distance within their peripheral the screen bars have been ass`er'nbled between shaft isv equippedwth plurality preferably the curved guides IB and I9. The breaker plate equally spaced vdisks A plurality of rods 43 shownas four in..number, extend through said and 26 the latter extending upwardly andOt-he edges. the rods being disposed 90 `apart. On said rear from the lower curved bar I9 andforwardly rods between the disksrse'el knives are Swing from the inner '0r upper u'vedgulqe 'Is- The ingly- ;connected ,.the rods passing through said guide 2 5 is longer than the'guidB-'z and extends, knives near one-end thereof.. 'I 'heseknives 44 on any one-of the rods 43 are mounted betweenalit serves, together with a thlrd guide angle bar ternate disks, as shown in Fig. 2. The outer ends 26a located above the breaker plate 2li,V to hold of the knivesnwhen they are extended radiany a. closure plate- It iS 0f COUTS@ t0 be-undeT--' outward from-the center of the shaft 38, follow stood that the guiding barf structure including. a, path slightlywithih the edges ofthe screen' the angle bars '25, 26 and 26a is duplicated 'at or grating bars 420.-(Fig. 1).. each side of the machine and that the breaker In .the operation ofgthe machine .theA shaft '39 is-rotatedfat high speed, approximately 1000 plate and the plate 21 above itat their ends are received and guided vby said angle guide bar Re P. M i anyysultable manner. It can be directly conn ectedA with an electric motor or through gearinginterposed between the motor and lthe vshaf| or asshown-in Fig. 2, it may be driven by a belt passing around a pulley 45 at knives, through centrifugal force are extended radially outward as in Fig'. 1.

'Ihe sand,- -dropping by gravitythrough the entrancechute 28,. isrstruck forcibly by-said knives 0f the endless beltvIYDeWh-ich delivers the Sand. and any'chnnksor-'massesof sandwhich adhere tothe upper end 0f the chute 28- The Pulley-.together arem edeet exploded apart, at 1eest adjacentthe upper end ofthe'entranxhute thelumps, chunks orbalis ofsand are disintea.

810ml@ Which the CODYQYOI PBSSBS S magnetici grated fand; the sand- '--grains :substantially sep- Chalatel S0 that heavier." Pieces 0f"i1'0n'-1Whih arated from each other and from any wood parts, may be in the sand are carried around the '-pulley nns orv-otherfmetai*parts'while the `burned sand', and do. not drop into the' upper end-of thefchute4 ashes and dust are also 'fully separated;

but drop from the conveyor beltafter".itslowergf'v y The'. 'suctidn fan: atvalsdraws. air from the inrun has been carried away fi-omif'thcifmagneuefy tenor of themaehmeupwardly'thrbugh the chim- Dlllley. However smaller 'pieces-"of ir'o; lnfs, wood"- ne'yf at 29'; wlfiiibli-l air-'jis'supplied' to. the'interior pieces and the like, will not bfdrawh-ithrgh the ofjthe 'rracliin'tlioughf p'enirig's'- at'31'.- This sand or be held with suiilicientorfand they-,`-` introducti'n''of-l tair' ur e'ii`s'. considerably the disks 42 and the knives 44 which have lthe action of a centrifugal fan or blower tending to draw air into the machine through openings 31 and distribute it radially. The light dust, ashes and the like are carried by the upward current of air and in this manner separated from the sand. The sand in its separated granular form will pass through the narrow slots between the bars 20. Any materials within the sand such as iron iins orother pieces of iron or wood oi any character, will not pass between the -vbars 20 but will be carried by the knives 44 around the bar grating or screen and will leave said knives and be thrown upwardly through the rear of the opening 34 into the domed housing 33 and striking the curved top thereof will be carried over unto the screen 36. Some of the sand particles will also be carried over unto this screen 36 andA will sift through the screen and drop back through the open lower part of the housing 33 into the interior o1' the machine. The screen 36 may be sufciently inclinedV so that particles dropping thereon will slideby gravity to its lower end and be disposed of through the pipe 36a.

The mechanism described and the process which is performed thereby is very practical .and useful for the renovation of molding sand which has been used and is to be reconditioned or renovated for subsequent use. The breaker plate 24 is of a heavy structurer in cross section for the reason that it is particularly subject to the wearing or abrasive action of the sand, as such sand is initially thrown against it with heavy force, the breaking up of the lumps being accomplished by the knives striking the sand and by the sand striking against the breaker plate 24. Such breaker plate as well as substantially all other parts of the machine which are thus subjectl to heavy wear are very readily replaceable in the machine which is of a structure such that its disassembly is readily accomplished. In such disassembly of the housing of the machine, particularly the upper part thereof which receives a very great portion of the wear, the shaft 38 and the parts `carried thereby are not disturbed. The upper part of the housing can be entirely removed by lifting it upwardly and can be replaced by lowering it from above with the shaft 30 and the disks and knives carried thereby remaining assembled in place. l

With the construction of machine as described, the objects and purposes of the invention above recited are completely and fully attained. The machine of course may be used for other purposes than renovating used molding sand, for example, in the `pulverlzing of limestone in preparing it for the manufacture of cement. The rotation of the shaft 38 has ybeen stated as in the neighborhood of 1000 R. P. M. but of course such rotation may be changed in accordance with differing conditions of operation. f

Having thus fully described my invention, what4 I claim and desire to secure by Letters Patent is sand as it enters the housing, an outlet chimney at the `upper part-oil the housing ,having a suction fan therein, a second housing adjacent said chimney above `and to one side of said knives and an inclined screen occupying a portion only of said second housing having its lower end leading to a point outside the housings, whereby the dust and ashes stirred up by said knives will be drawn out through the chimney and the lumps will be thrown upwardly on top of said screen `to carry out solid refuse and permit the sand particles to be returned to the main housing;

2. A machine for renovating molding sand having therein ashes, dust and portions held together in lumps comprising, a main housing to receive said sand, a plurality of rapidly rotating knives in said housing to contact the sand entering therein, an outlet chimney having a suction fan therein, a second housing in the upper part of said main housing above and to one side of said knives, and an inclined screen in said second housing terminating outside thereof and occupying only a portion thereof to provide a passage between the screen and a side of the second housing, whereby the dust and ashes stirred up by said knives will be drawn out through the chimney and the lumps will be thrown upwardly through said passage onto said screen which will carry out the solid refuse and permit the sand particles to return to the main housing. v

3. A machinefor renovating molding sand having therein ashes, dust and portions held together in lumps comprising, a main housing to receive said sand, rapidly rotating means in said housing to contact the sand entering therein and stir up the dust and ashes and throw upwardly the lumps therein, a second housing in the upper part of said main housing above and to one side of said rotating means, a screen in said second housing, a passage in said second housing to receive the up- -wardly thrown lumps and direct them to said screen, whereby the solid particles of the lumps particles permitted to return to the main housing, and means for withdrawing from said main housing the dust and ashes stirred up by said rotating means.

4. In a machine of the class described, a housing into which used molding sand is adapted to be delivered, the lower side of said housing being open, a pair of curved guide bars spaced from each other located at the inner side of each side of the housing, spaced apart removable grate bars carried at their ends between said guide bars, pivotally mounted reversible spacers on some of said bars, means for holding the grate bars against' movement, a horizontal shaft, swinging knife members connected with and movable with said shaft, said knife members at their outer ends lying slightly within the inner edges of said grate bars, suction means for withdrawing ashes, dust and light materials from the upper portion of the housing,a domed housing located-above the upper side of the front portion of the sand receiving housing, there being an opening from said sand receiving housing to said domed housing at the lower front portion of the latter, and conveyor means mounted in said domed housing for disposal of heavy materials thrown upwardly by said knife members into the domed housing. l WlLLARD J. BELL.

,will be carried away and the remaining sand 

